1. Field of the Invention
The present invention relates to a variable inductor, and more particularly, to a variable inductor element used in a mobile communications device, or the like. Moreover, the present invention also relates to a method for adjusting the inductance of a variable inductor.
2. Description of Related Art
With advances in compactification and higher frequency operation of electronic devices, there have been accompanying demands for compactification and higher frequency operation in passive elements, such as inductors, and the like. Inductors are problematic in that (1) they are more difficult to fabricate in a coil shape compared to other passive elements, and (2) increased operating frequencies are difficult to achieve due to the parasitic capacitance between the inductor and the substrate. Moreover, a structure for an inductor which is capable of altering the inductance is known, wherein the inductance is adjusted by cutting (trimming) a trimming wire provided in the coil, by means of a laser, or the like, as disclosed in JP-A 2000-223318 (FIGS. 1 to 3).
However, in the method disclosed in the above document, since the inductance is adjusted by cutting a trimming wire by means of a laser, or the like, it is not possible to restore the trimming wire once it has been cut, and hence a problem arises in that the inductance cannot be adjusted in a reversible manner. Moreover, adjustment of the inductance by cutting a trimming wire only permits the inductance to be changed in a step-like fashion, and does not allow continuous adjustment of the inductance within a prescribed range.